The Implementation Of ONU Device In The EPON-WiMAX Integrated Access Experimental System

EPON has the advantages of high-bandwidth and low-cost, and it gradually becomes the mainstream of cable access technology. WiMAX is the new technology for broadband wireless access network, which supports for high-bandwidth and flexible access. Therefore, If combining the advantages of these two technologies by integrating these two technologies, we can take full advantage of high bandwidth and long transfer distance of optical access, and flexibility and mobility of wireless access. The integration of EPON and WiMAX has become an important development tendency of optical access and wireless access. At the same time, To meet the time synchronization requirement in the wireless backhaul network, as an mobile backhaul network, EPON should supply time synchronization information for them. As one kind of time synchronization technology based on packets, IEEE 1588v2 can reach the precision of submicrosecond, which can fully meet the time synchronization requirement in the mobile backhaul network.With the support of national 863 project "The architecture and key technologies of dynamic, heterogeneous and integrated access networks, supporting P2P and multicast integrated services", this thesis is mainly deployed on the implementation of the WiMAX board in the ONU, and EPON system supporting IEEE 1588v2 protocol. The main contents of this thesis are as follows:1. Functional requirements of the EPON-WiMAX integrated access experimental system have been analysed, and the WiMAX board in the ONU has been designed.2. Core functions of the WiMAX board in the ONU have been implementated by FPGA. After understanding the structure of the WiMAX board in the ONU of the integrated system, this thesis has completed the analysis on function demands of the WiMAX board in the ONU, division of the modules, and implemention these modules, including Ethernet frame encapsulation module, Ethernet frame classification and decapsulation module, queue management module and transmission control module.3. The time synchronization function in the EPON system has been implementated based on IEEE 1588v2 protocol. This thesis has studied the fundamental of IEEE 1588v2 protocol, analysed the factors which could affect the accuracy of time synchronization, designed scheme of EPON system supporting the IEEE 1588v2 protocol, and implementated the master clock module in the OLT and the slave clock module in the ONU. Experimental result shows that, for the master clock and slave clock with frequency stability of±30ppm, in the case of independent oscillation of the clocks in the OLT and ONU, the maximum time difference between the master clock and slave clock does not exceed 30ns, which can meet the time synchronization requirement in the mobile backhaul network.